Anatomy Summer Class Chapter 5

Which of the following statements is/are TRUE of the growth of the skeleton?

It begins to ossify at six weeks of gestational age

The deposit of calcium salts within a tissue is called ________.

calcification

A small, flat articular surface is a ________.

facet

Roofing bones of the skull form via ________ ossification.

intramembranous

The skeletal system participates in ________.

maintaining blood calcium levels

Which is a major function of the skeletal system?

support of the body

Small, flat, oddly shaped bones that develop between the flat bones of the skull are called ________.

sutural bones

Perforating canals ________.

transmit blood vessels to osteons deep inside the bone

A smooth, grooved articular process, shaped like a pulley, is a(n) ________.

trochlea

Bones have a vascular supply that is ________.

very extensive, including many arteries and veins branching throughout the bone

How do hormones regulate the pattern of bone growth?

They change the rates of osteoblast and osteoclast activity.

A bone cell that secretes the organic components of bone matrix is ________.

an osteoblast

Which diagnostic procedure detects abnormalities in synovial fluid?

arthrocentesis

Which of the following is produced within red bone marrow?

blood cells

The simultaneous process of adding new bone and removing previously formed bone is called ________.

bone remodeling

Because they resist stretch, the ________ fibers provide the tensile strength of bone.

collagen

A prominent ridge on a bone is called a(n) ________.

crest

Which of the following type of fracture produces new and abnormal bone arrangements?

displaced fracture

Blood vessels that supply the ends of long bones are called ________ vessels.

epiphyseal

A long bone increases in length until ________.

epiphyseal closure occurs

An elongated cleft is a(n) ________.

fissure

Diploë is spongy bone found in ________ bones.

flat

The scapula is an example of what type of bone?

flat

The expanded articular end of an epiphysis, separated from the shaft by a narrower neck, is a(n) ________.

head

Endochondral ossification begins with ________.

hyaline cartilage

The vessels supplying blood to the inner (diaphyseal) surface of each epiphyseal plate, where bone is replacing cartilage, are called ________ vessels.

metaphyseal

Which of the following acts on the intestine, requiring calcitriol production by the kidneys?

parathyroid hormone

As a long bone develops, the point where osteoblasts first replace calcified cartilage with spongy bone becomes the ________, from which further development proceeds.

primary ossification center

An extension of a bone that is set at an angle to the rest of the bone is usually called a ________.

ramus

Each year, approximately ________ of the adult skeleton is demolished and then rebuilt or replaced.

1/5 (20%)

Which of the following occurs during endochondral ossification?

The bone grows in length and in diameter.

Bone mass reduction occurs initially between the ages of ________.

30-40

If a long bone that was found at an archeological dig contained functional epiphyseal plates, what inference is most accurate?

The person was not mature.

After a fracture occurs, a(n) ________ forms as a network of spongy bone unites the inner edges.

internal callus

The epiphyseal cartilage connects to the diaphysis by a narrow zone called the ________.

metaphysis

________ are struts or plates within spongy bone which assist in withstanding stresses in a specific direction.

trabeculae

Which of the following is an example of an irregular bone?

vertebra

Which of the following is the active form of calcitriol?

vitamin D

Which of the following is most likely to have a nerve pass through it?

foramen

An example of a pneumatized bone is the ________.

ethmoid bone

A shallow depression on the surface of a bone is called a ________.

fossa

The degenerative effects of osteoporosis are most likely to affect ________.

older women

In osseous tissue, which of the following is always removing matrix and releasing minerals?

osteoclasts

Mature bone cells that maintain and monitor the protein and mineral content of the surrounding matrix are called ________.

osteocytes

The physical process of bone formation is called ________.

osteogenesis

Which type of cell divides to produce daughter cells that can differentiate readily after a bone is cracked or broken?

osteoprogenitor cell

Regarding long bone formation, bone development proceeds from the ________ in the shaft.

primary ossification center

Which of the following is important as a stimulus that maintains normal bone structure, especially in growing children, postmenopausal women, and elderly men?

regular exercise

The function of an osteoclast in osseous tissue is ________.

to dissolve old bone matrix and release amino acids and the stored calcium and phosphate

An individual with otherwise normal features, but having very short limbs, may have a condition known as ________, in which epiphyseal cartilages grow unusually slowly.

achondroplasia

The yellow marrow that fills the medullary cavities of many bones is dominated by ________.

adipocytes

A ________ is a smooth rounded articular process.

condyle

Osseous tissue is classified as which of the following?

connective tissue

The walls of bones are composed of ________.

compact bone

In addition to osseous tissue, a typical bone contains ________.

A) other connective tissues B) smooth muscle tissues (in blood vessel walls) C) neural tissues All of the answers are correct.

The endosteum is best described as ________.

A) a tissue that is active during the growth or repair of bone B) the lining of the central canals and perforating canals C) a layer that covers the trabeculae of spongy bone D) an incomplete layer that sometimes leaves matrix exposed All of the answers are correct.

Which of the following describes a central canal?

A) contains an artery B) contains a vein C) runs parallel to osteons D) also called Haversian canal All of the answers are correct.

During endochondral bone formation, ________.

A) the matrix of the cartilage model becomes calcified B) cells of the perichondrium differentiate into osteoblasts C) capillaries and osteoblasts migrate into the heart of the cartilage D) osteoclasts erode the center of the new bone to form a marrow cavity All of the answers are correct.

How does an extensive exercise program affect the appearance of the skeleton? Why do these changes occur?

Answer: Because bones are adaptable, their shapes and surface features reflect the forces applied to them. For example, bumps and ridges on the surface of a bone mark the sites where tendons attach to the bone. If muscles become more powerful, as what happens as a result of an extensive exercise program, the corresponding bumps and ridges enlarge to withstand the increased forces. Heavily stressed bones become thicker and stronger, whereas, bones not subjected to ordinary stresses will become thin and brittle. Regular exercise is therefore important as a stimulus that maintains normal bone structure, especially in growing children, postmenopausal women, and elderly men.

What kind of tissue(s) would most likely be found in a tissue sample taken from the interior of the epiphysis of the femur?

Answer: Spongy bone makes up the internal framework of the epiphyses of the femur. Also found here are extensive areas of red bone marrow (important sites of blood cell formation) filling in the spaces of the spongy bone.

A boy returns to school to begin 7th grade after summer vacation only to find that he is at least four inches taller than several classmates that were the same height as him before the summer. Propose a reason for such a difference.

Answer: The boy has most likely entered puberty and his classmates have not. He has experienced rapid growth as a result of increasing sex hormone levels in his body. These hormones stimulate osteoblasts to produce bone faster than the rate of epiphyseal cartilage expansion. Over time, the epiphyseal cartilages will narrow and eventually ossify, or "close."

What is the significance of the orientation of the trabeculae in spongy bone? Provide a specific example, discussing how trabecular structure lends to its function(s).

Answer: Trabeculae grow in response to stresses on the bone, to act as buttresses in the bone; therefore, they align at right angles to the direction of the stress. For example, the trabeculae in the proximal epiphysis of the femur are oriented long the stress lines, but with extensive cross-bracing. This trabecular alignment function in transferring forces from the hip across the metaphysis to the femoral shaft; at the distal epiphysis, the trabeculae direct the forces across the knee joint to the leg. In addition to reducing weight and handling stress from many directions, the open trabecular framework provides support and protection for the cells of the bone marrow.

What is the mechanism of marrow cavity enlargement in a long bone?

As bone matrix is added to the external surface, osteoclasts remove matrix in the center of the bone to enlarge the cavity.

During track and field practice one of the runners trips over a hurdle and falls forward. Fortunately, he is able to break his fall with his hands. However, he stands up holding his wrist in pain. What type of fracture might he have sustained?

Colles fracture

A(n) ________ fracture occurs at the ankle and affects both leg bones.

Pott

Which of the following describes how bones are innervated?

The periosteum, endosteum, medullary cavity, and epiphyses are innervated by sensory nerves.

What is the fate of the chondrocytes that are present where bone is forming?

They die and disintegrate, leaving cavities within the cartilage.

A break in a bone is called ________.

a fracture

Increased levels of calcium in the blood of a pregnant woman would stimulate the secretion of ________, which would increase calcium loss in the urine.

calcitonin

Calcium phosphate interacts with ________ to form hydroxyapatite.

calcium hydroxide

Because they are strong and relatively inflexible, ________ enable bone to withstand the stress of compression

calcium phosphate crystals

As cartilage enlarges in step 1 of endochondral ossification, ________ near the center of the shaft increase in size.

chondrocytes

Layers of bone that occur at the external and internal surfaces of the bone are referred to as ________.

circumferential lamellae

Organic components of the matrix of bone include ________.

collagen fibers

The periosteum ________.

covers the outside of bones

Treating a compound fracture differs from other fractures most significantly due to ________.

risk of infection

Which of the following is a classification of bone shape?

sesamoid

Differences in body size and proportions between males and females result from the different effects of ________, which affect(s) the growth of the bones.

sex hormones

A chamber within a bone, normally filled with air, is a(n) ________.

sinus

A fracture of a bone that is the result of a twisting stress that spreads along the length of the bone is called a(n) ________.

spiral fracture

The two types of osseous tissue are ________.

spongy and compact bone

Which of the following is a special characteristic of spongy bone?

trabecula

Spongy bone is made up of a network of bony spicules arranged into parallel struts or thick, branching plates called ________.

trabeculae

Processes that form where tendons or ligaments attach to a bone include ________.

trochanters, tuberosities, and tubercles